The present invention is directed to shaft construction and, in particular, to the construction of interior walls in mine shafts and other excavation.
In the construction of a mine shaft, peripheral walls generally define the shaft and provide support to hold out the surrounding earth. In addition to these peripheral walls, it is often desired to provide interior walls, a common type being a curtain wall, which extends longitudinally through the shaft to divide it into two or more parts, one or more parts serving to provide ventilation and the other parts serving as, for instance, an elevator shaft.
A common method of constructing such walls in the past has been to provide opposed, longitudinally extending channels in the peripheral walls. Reinforced-concrete panels with side edges received in the opposed channels are lowered one at a time through the shaft. The side edges of the panels have a natural tendency to bind in the channels because it is impossible as a practical matter to keep them perfectly parallel to the channels walls while they are being lowered, and slight rotation from a parallel orientation results in binding. In the case of a vertical shaft, therefore, the normal way to lower through the shaft is to alternately "work" it into place, i.e., to apply and release an upward force on the panel so that it pivots slightly. This brings the panel momentarily into an orientation in which its side edges are substantially parallel to the walls of the channel and the static friction between the panel and the channel walls is overcome by gravity. The panel accordingly drops a short distance and binds again. This operation is repeated so that the panel is lowered in a stepwise manner to its assigned location. The next panel follows in a similar manner until it rests with one of its edges abutting one of those of the previous panel.
This method of wall construction is advantageous because it allows the individual reinforced-concrete panels to be constructed outside of the shaft. However, the stepwise process of maneuvering the panel through the shaft is time-consuming. Furthermore, it makes scheduling the construction of different shaft-structure parts inflexible, because the panels cannot be lowered if there are any intermediate platforms in the shaft that extend into the space between the channels. These problems exist not only for vertical shafts but also for diagonal or horizontal ones.
It is accordingly an object of the present invention to construct interior shaft walls in a more-rapid manner and in a manner that permits more flexibility in construction scheduling than was possible in prior-art methods.
Further, it is an object of the invention to provide improved panel structures which facilitate the construction of interior shaft walls.